Portion of a shoe midsole



FIG. 1 is a front perspective view of a portion of a shoe midsole showing our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a side view thereof; and,

FIG. 4 is a rear view thereof.

The uneven broken line segments extending from the polygonal elements within the shaded area form no part of the claimed design. The uneven broken line immediately adjacent to the shaded area represents an unclaimed boundary of the design. The uneven broken line showing of the remainder of the shoe is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a shoe midsole, as shown and described. 